This invention relates to the field of video conferencing technology and specifically to a method for automatically determining the appropriate pan, tilt, and zoom parameters of a camera which correspond to desired views of participants in a video conference setting.
During a video conference it is necessary to know the appropriate camera parameters for each participant so that the view of the camera can change quickly from one participant to another. These parameters include the appropriate zoom, pan and tilt of the camera—and will collectively be referred to as the camera “parameters” with the values of these parameters associated with each participant being the “presets”. While the conference is occurring, users require the ability to be able to view different participants quickly; frequently changing from one participant to another in a small amount of time.
Prior art devices require a user to manually set the camera parameters for each participant involved in the video conference. Each camera being used is focused on a participant and a preset switch is actuated. For example, if there are three people in the conference, switch 1 is used to represent the appropriate camera parameters for participant 1; switch 2 for participant 2; and switch 3 for participant 3. When a user desires to switch the view between participant 1 and 2, he only needs to activate switch 2 and the camera is moved and focused accordingly. However, setting a camera for each participant is frequently a tedious process requiring a commitment of time by the camera operator or user. Additionally, every time a participant leaves or enters the room, the presets have to be readjusted accordingly. If a participant merely moves from his original location, the original camera presets will no longer apply. Clearly this is a problem if a participant moves from one location to another within the room. However, even if the participant moves within his own chair (i.e. forward, backward, leaning toward one side, etc.) the parameters may change and that participant may no longer be in focus, in the center of the camera's view, or of the desired size with respect to the camera's view.
In U.S. Pat. No. 5,598,209, a user can point to an object or person it wishes to view and the system automatically stores the pan and tilt parameters of the camera relating to the center of that object. However, all of the objects or persons in the room have to be affirmatively selected and stored under control of a user which again is time consuming. There also is no provision for updating the parameters when a participant leaves or enters the room.
The ability to automatically determine preset positions is useful in a congress layout as well. Generally, in these types of rooms, the camera presets are based upon the microphone being used for each individual. When a participant turns on his microphone, the camera presets that relate to the position of that microphone are used. This is problematic because if the microphone does not work or if one particular microphone is used by another speaker, the appropriate correlation between speaker and camera view would not occur.
Therefore, there exists a need for a video conferencing system which automatically determines the appropriate camera parameters for all participants and which can also adjust itself as participants enter and leave the room. The goal of a video conference is effective communication and conversation. If a user continually has to readjust the system to initialize or update preset parameters, this goal is frustrated. The conversation dynamic between end users is different from that of a production (as in a television show). To facilitate this dynamic, it is desirable to automate as much of the system as is possible without resorting to a static zoomed out view which would yield less meaningful communication.